This post is to advise a cheap way to safely view your fusor grid assembly. It is important that some method be devised for viewing the grid of your fusor while it is in operation. This is to get an idea about a number of factors that tell the observer how their fusor is operating and warning of issues that can arise quickly.

A good view of the grid while operating can be very telling and can indicate the following.

1. Too high an operating pressure - No central spot or a diffuse glow around the grid.
2. Too low an operating pressure - Failure to obtain a glow at any voltage.
3. Good operation at any voltage, current or pressure - Small central poissor and bright star mode rays.
4. Too high a voltage and current for conditions - Grid rapidly heating from red to orange to white heat. (near destruction)
5. Too large a filter capacitor in power supply - grid glow pulsing on and off.
6. Indicating it is now OK to up the voltage - When a grid goes from red or orange hot to lower temperature at a given pressure and current.

There are many ways to view your grid. The assumption, in this FAQ, is that you already have a suitable view port installed.

One of the safest and most detailed way to view your grid is via an inexpensive single board camera. Color is not really needed at all in this endeavor. A good 12 volt DC camera can be found for around $30.00. Select an NTSC output camera with a very wide angle lens that can be focused easily. You will find many used, inexpensive video monitors to hook to the camera for remote viewing. The monitor can be a small 9-inch monitor or as large as an 80-inch giant LCD flat panel. Any number of video recorders can record the image off the NTSC camera while you watch.

Computer cameras with USB connections can also be had. The choice is yours.

EDIT! ... Thanks to Bob Reite for a followup reply below. ..... Related to number 4 above.......
All cameras are IR sensitive and, as such, a white hot looking grid in the video is not necessarily white hot! It might only be red or orange hot and not immediately ready to melt. This is actually a good thing as it is a safety valve, frightening you and alarming you to the fact that your grid is approaching a danger point, allowing you to "back off" and make adjustments to protect it with lower pressure and or lower current/voltage. END of EDIT....

Mounting...........

The mounting of the camera can be fancy, and elaborate, or simple. The mechanical issues, you will have to work out for yourself.

If the view port is floating at some odd angle, a small metal frame may be required to mount it in some fashion to the Conflat fitting. A suggestion might be to use a piece of all-thread rod through one of the view port's mounting screw holes with nuts on each side to provide the normal pressure to secure that area of the flange with a 1 or 2-inch part of thread extending out from the flang to secure your camera mount.

Any mount should provide for the adjustable camera lens to be pressed, centered against the glass viewport. It is also good to provide a nice light shield tube that also presses against the flange outer rim to exclude ambient light as well. All this must be part of your mount's design to work in a symbiotic fashion with the flange, once mounted.

It is a good idea to pre-focus your camera lens prior to making the mount. Hook the camera up to a power supply, hook it to your monitor, and run your fusor. You can run it at 20-30 microns with air if you wish and very low voltage, 3-6kv. You are looking for the glow and the grid wires to show clearly. Press the working camera up to the glass and focus the lens to obtain a sharp image of the grid wires. If the lens can be secured with a set screw, do it now; if not, a tiny blob of silicone glue on the lens thread will do the job.

NOTE: be sure not to kill yourself by contacting the HV terminal on your fusor while doing the above procedure!!! It is a wise idea when planning a fusor design to situate your view port far from the HV terminal. This avoids electrical noise and possible arcing to the camera and its power and video cables, which should be dressed such that they are going away from the HV terminal in any event.

You are very much on your own here.

How I did it on fusor IV................

I have attached images of the mount I used on my fusor IV construction. First is a typical PC board camera. The one shown has a great macro focusing lens that has a set screw to lock the focus if desired. Its resolution exceeds what the average user needs.

Click each image to enlarge!

On Fusor IV, I placed the HV terminal on the top of my fusor and the camera view port on the bottom for safety's sake. I did not need to make a fancy mount as the fusor height was adjusted by machining the vertial supports to allow the camera to rest on the fusor platform looking "up" at the grid. A simple phenolic shroud excludes stray ambient light. The pictures should be worth a thousand words.

Richard Hull

Attachments

Typical single board camera - $30.00 - no supply, no ready to use cables....Easy to hook up

Taken during construction, 2004. Shows how the fusor was mounted.

Nice view of system in operation with monitor near controls to monitor operation. circa 2009

closeup view of setup.

Close up of camera and light shroud with base used to adjust and press len up against the glass viewport

Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

I just wanted to add my camera as another example. I simply bend and drilled a piece of iron. The iron is attached to the conflat flange by a long bolt as you can see in the picture. Then I attached a small webcam to the iron with a small bolt the cost of this is around $25 (including the new webcam). Because this system is facing toward me, I placed a lead glass between the viewport and the webcam. Then I cover the whole thing with a lead box I got for free from an x-ray machine dealer.

Something to remember if you use a color camera, which is what I did since I had one lying around, is that IR from your grid is going to go right though the camera color filters and will show as "white hot" in the monitor, even though it's only a red or orange glow in real life. Below are pictures of my grid operating at 10 KV, 10 mA under 5 microns of pressure with air.
"Real Life" photo. Grid shows as "orange hot". The black square blocking the view is the "cube" video camera.

Monitor image. Grid shows as "white hot".
But at least this will cause you to err on the side of caution while operating your fusor.

The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.

The camera's IR sensitivity is impressive and can save a lot of grids by scaring the daylights out of you in thinking your grid is about to melt. As you note, you will err on the side of caution. Thanks for adding this. I forgot to mention it. I have edited this into the original FAQ and credited you, Bob.

Richard Hull

Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.